earlwb

I understand you OK. Thanks for the information.

captinjohn

first ring is pressure ring, second ring is oil ring, they are with different shapes and functions. third groove idea is from glow engine piston store some oil anddirt while engine running.
made a solution for supercharging and lubricating, there are two nipples on INTAKE MANIFOLD, and two nipples on Back cover. need be connected with pipeline.
Two nipples on Intake-Manifold: one is no pass to intake-manifold but pass to Walbro carb, one connection from back cover, so the pressure from crankcase to carb via this nipple to supercharge.
one nipple is pass to intake-manifold and connected from another nipple on back cover.
So, when piston move from TDC to BDC, the pressure from crankcase boost to carb and manifold via two connections.
when piston move from BDC to TDC, the negative pressure from crankcase will suck gas mixture to crankcase via the another nipple connection （not from carb connection nipple, one-way）, to lubricate the roller bearing, and there is a hole inside the crankshaft, the oil transferred into cam gear for lubrication via this hole.
when engine running, the carb will pump twice for each cycle, one is effective pump, one is noneffective, and now make second noneffective pump to send oil to crankcase for lubrication via the seond nipple on manifold to second nipple on back cover.
I am sorry it is hard to explain with my poor English.

MaybeMichaelchow should have left the word dirt out !

Turk1

Another NGH35 CC maiden on a Su 29 Sebart plane.The air was so stormy that plane had a little problem on landing.
http://youtu.be/9omR3-P4nlY
[youtube]http://www.youtube.com/watch?v=9omR3-P4nlY&feature[/youtube]

the pope

Howdy Turk , I dont think Ide like that plane heading at me unrestrained taxing out to the runway . That strip is awfully close to the pilots stand as well. I guess Im getting a bit chicken as I get older . The engine pulls pretty good though . Enough of the sermon , cheers from the pope

Turk1

Hi ANZAC,you are right for the taxiing.It s forbidden to taxi  inside pit area but somedays when only a  few guys together, they dont respect much.
That club has had much difficulties to have the area and build.So they have to keep it compact.
Im not flying there.

TimBle

Flies well and the Sebart 1.40 SU29 is a fairly large aircraft in that class. Quite impressive

mchandrayan

Hello
Mr Chow
Please refer the attached picture, there seems to be difference between the supplied piston (for Rear exhaust conversion) and the picture on the manual. The transfer port cutout on the piston shown in the diagram is missing from the actual piston. Could you please clarify which one is correct.

Any one else who has seen the innards of the RA may also chime in please

Turk1

Hi ,your piston on pic. is the right one to use for rear exhaust.Dont worry.
Mr.Chow should be on a long holiday  for now because of Chinese new year .

mchandrayan

Thanks Turk
But then why is the difference in the picture shown in the manual and the actual piston. Wouldn't the absence of cutout degrade the performance, since charge being transferred to the combustion chamber would be lesser.
Or is it that the manual picture is wrong?

Turk1

Hi,I dont have any idea about such a piston transfer system on NGH 35 but as it is a liner type engine,there is no meaning such a piston help transfer port(I may be wrong).But, Im sure your piston is the same with other NGH35 boxes have inside.

peakay

I think the main reason is the cutouts in the piston are for lube to the gudgon pin and not need when the liner is spun for the rear exhaust. Just a thought.

j301

My Feedback: (12)

I put an NGH 35 on a CMP P40 (swapped out an ASP (magnum) 180 4 stroke). It ran/tuned fine static, but on the first flight the motor bogged more and more as the plane went down the runway. Out of space and too far to stop I got it in the air hoping it would clear itself but it just became worse once airborne, dropped to less then 50% power or more. Caused a snap before I could get it back around. Lost the plane but the motor is ok. Is there an issue with the carb being in front, i.e. is the airflow disturbed/turbulent in some way I need to compensate for, or do does the carb need to be tuned "not to its best" one way or the other (rich/lean) on the ground? I plan on putting it in a 120 size corsair but am afraid of a repeat. Any suggestions would be greatly appreciated, thanks!
Jim.

johnboy151a

My Feedback: (68)

I have one of these engines still NIB for a future project, so you problem has my full attention.....

John

j301

My Feedback: (12)

If you rotate the exhaust port to the rear, be very careful when putting the piston back in, make sure the ring stays lined up with the notch or else you will be waiting a couple of days for a new ring to come in...(don't ask me how I know that....[:@]...) Seems to run fine on the ground during break in, and it ran fine in the plane while sitting still. The cowl on the P40 was right up the the carb, (inverted and right behind the intake) in fact I had to trim part of it to fit, that's why I'm wondering how it will do in a round cowl. Hoping someone in the know might still be watching this thread.

Turk1

I have several friends here flying GT35 engines ,there is no such a problem I met yet.Mostly adjustments needed to renew time to time and especially muffler bolts needed to care(slips easily ).I guess your tank/clunk may have a problem.Did you check your oil rate in fuel?(heavy fuel than carb. can allow??)

j301

My Feedback: (12)

I know the clunk/fuel system was good as part of the p40 postmortem, I was still running the 25/1 mix as per the manual. Will likely not do that again, more like 32/1.

johnboy151a

My Feedback: (68)

Anymore on this problem?

John

Turk1

Another thing I remember to warn about this particular engine.Side exhaust is exposing danger to melt the fuel line to carb. So please take care of it to make other way onto carb. fuel nipple from tank.

j301

My Feedback: (12)

Had mine rotated to rear exhaust mode. I'm just going to install it in the new bird and taxi all the way down to the end of the runway before take off. This way if it burbles, I will get off it while having room to roll out, and try some tuning. If I cant work it out I will just bench it all together. Either way, I'll let you know how it goes.

mchandrayan

Here is my experience with the engine thus far

Pros-
- Great Power- Was on GW MXSR 30 cc and then now on World Models (160 Glow size) Extra. Mostly fly the Extra at 1/2 throttle. The engine has been converted to rear exhaust
- Easy handling and starting. Hand starts are easy and so are electric starter.
Cons -
- The muffler started coming loose after 3 flights, not only the main 5mm bolts but the 2 (out of 6) 3mm outer bolts had vanished in thin air.
Apparently this was due to the muffler base and muffler halves gasket burning off, which left a void and thus the bolts become loose. With a rear exhaust muffler it is pretty difficult to spot the problem and especially if the engine is cowled. You sure can not open the cowl after every flight to check integrity of everything.
- Every time you have to take off the muffler you need to open up 6, 3mm bolts and replace two sets of gasket. Costly?? Not much but a pain.

So here is a question for Mr Chow and others using the engine? How do you ensure that the muffler screws do not fly off? Will thread lock work in such a high heat environment?
Are you using stock gaskets for the muffler or cutting your own?
And lastly the spark plug is said to be CM 6. I picked up a NGK CM6 and the NGK plug is longer than the one supplied with the engine. Can I still use the original NGK plug?

Turk1

Hi Mchandrayan.Also you should pay attention to not to stripping  those screws.First batches were suffering of such problem too.Then fixing is anounced.
You can use nordlock washers to make sure impossible to get loose unless you do.

mchandrayan

So how do you identify if the engine is from Initial batches or later ones where supposedly the problem was fixed? And what was the fix? Any ideas? Why is the fix not publicaly announced? Afraid of liability?
And as for nord lock fix the bolts are of just enough length if I use a nord lock it would further reduce the thread length so what do one do? Buy longer length?

Will thread lock survive?
And how about those gaskets which seem to be made of ordinary fibre and burn off? Did NGH fix that?

Turk1

Hi, the fix was to change the screw thread size (I guess) or type.
I dont think gaskets burn off,instead they should be easily ripped because of loose screws.

mchandrayan

Oh well
I have remanats of the burnt gaskets will post pictures
And many of my pertinent questions still remain unanswered would like to see Mr Chow answer these
Thanks

Turk1

Hi MChandrayan,here some of my friends have NGH 35 engines and flying frquently,they have met some loose screw problems,some stripping screw problems but none of them have met "burnt gasket" problems.They lost muffler gaskets because of loose parts but not burnt.
I have NGH 9 engine on bench to run tests time to time and I also dont have any burnt gasket.They made of klingerit.I agree worst Klingerit in  the world but Klingerit.It is hard to burn it.